mudguard

Thanks for all the suggestions on this thread, and indeed during my four years of ownership. Not many get to have the privilege of owning such a machine as their first car. I've sold the Seven - with, of course, full disclosure of its difficulties. I'm sure it'll be sorted out and be back on the road making its next owner very happy. For me - not quite sure yet what's next. Maybe another Seven, or maybe I'll try something else. Nothing will ever live up to it, I'm sure. Many fond memories of chip runs, weekend blats with the Kent and Sussex groups, Dunsfold, the evening meets at Toys Hill and Penshurst, all with great camaraderie from you. And outside of the club, most corners of England and Wales, and a bit of France, 28,000 miles. Thanks - it's been a blast!

Could be, but my feeling is this is less likely. The reason why I think this is that the original cat was already destroyed before the HG work, by (presumably) the same problem which has now, 8 months later, apparently destroyed the second cat. This problem appears to be overfuelling, root cause unknown, so it seems reasonable to think it's been the same problem all along, and not detected and corrected during the HG work.

No verniers, stock pulleys, stock cams, stock everything really.

Yes, but the major "misfire" lasted one day 6 weeks ago and vanished immediately on cleaning the HT springs. The symptoms were two things it has never done before or since: On idle, run very rough, hunt and never settle. On acceleration, stutter and then recover. The other "misfire", the more long-running one, whose onset was immediately after the HG work, seems strictly idle-related, and this was improved significantly by cleaning the IACV. The symptom of this is occasional stumbling and sometimes stalling when slowing down, and then (if not stalling) recovery to a fast idle, and then settling down. Absolutely no stutter under acceleration, and no idle hunting. The reason why I think these are not the root cause of the cat failure is that they both began long after the original cat was in significant distress.

Like this:

That's my feeling too Andrew. And as for easily passing the emissions test; I found the 2017 report - lambda 1.016, CO 0.07%, HC 29ppm. I don't recall ever seeing the 2018 numbers, and I don't have the 2019 numbers to hand (2019 was about 4 months pre HG work), but I remember thinking at the time that it had just scraped through on the lower boundary of the lambda, but not understanding the significance of that. So if I'm remembering correctly, something started to go wrong in 2018 or early 2019, which would make it completely unrelated to the HG work. Perhaps, even, the cat destruction that was addressed during that work was nothing to do with the overheating, but this other, earlier problem, which has remained unresolved ever since, and will keep eating cats. It's like a detective puzzle!

Lambda sensor has been changed, and spark plugs. Old lambda was badly sooted, believed to be caused by a spark plug related misfire. The outgoing plugs were 2-year-old NGKs, replacing the - believed - original Rover plugs, which in 2018 were still in good condition after 16 years. Runs better, but emissions are worse, and apparently this means the soot has gone into the cat and destroyed it, so needs to be replaced. The car got through an MOT with the old near-destroyed cat last year. No mention of checking ECU temperature sensor, ODB2 diags, injector cleanliness, injector leakage, air filter health, cam timings, exhaust leakage. To their credit they're willing to back up their convictions and try to borrow another cat as a test. If they're right I'll happily cough up for a new one.

Standard MEMS3.

It's a 2002 kit build, first registered Jan 2003. As far as I can tell, it's always been subject to emissions testing. Certainly all MOTs in my ownership (4 years) have. And it's always passed emissions, until now.

No TBs, just standard VVC (silver) ally inlet with single throttle for all 4. Would anybody be able to recommend a specialist to do the sort of work being suggested?

Thanks for that Opplock. From my reading of that thread, the "correct" wider lambda limit (0.95-1.09) was applied and the car failed even that by a whisker (0.94). However, the big problem appears to be CO rather than lamdba; the car is measuring at > 6x the permitted CO maximum. Which would seem not to be a case of a slightly wrong limit applied?

It was just a skim. I don't have the car as I didn't want to drive it the long distance home following the failed test. It's now sitting in CC's workshop (they presented it for MOT) and whilst they're trying very hard indeed to be helpful they don't seem to be completely sure what to do next - K series emissions seem not to be a core part of workshop knowledge these days, which is understandable to an extent. They want to change the lambda, and they have a new one available - which seems a good idea to me especially as the old one is partly melted. They also want to change the cat, which is going to be a long delay as none in stock, which I'm resistant to especially as it seems not to be a cat problem. I think I'll ask them to clean the injectors as well as change the lambda, and then see where we are on emissions. I'll also ask them if they know how to check the cam timing on a K. I don't mind spending a bit on trying to get it through, because if it can't pass, I really don't know what's going to happen to the car. It's quite sad really.

Thanks Andrew, that's very helpful. Lambda is on no.4 primary in the engine bay, it's 4 primaries out to side of car then a collector there into 1 ahead of the cat. The ECU could be thinking the engine is too cold. The thermostat was changed to the summer type due to the winter type not opening due to surge of coolant into the expansion tank due to historic removal of the ball valve in the inlet manifold - as previously discussed on a thread here. The thermostat now opens 100% reliably, but the temperature sticks at around 65, which is quite a bit lower than its previous normal running temperature of 80. But I believe plenty of Ks are on summer thermostats with no issues. The cat gets very hot as it should, but the old damaged one stayed cool. Air filter was cleaned this year - seems to be in good condition. The car felt considerably better after the HG work - it became able to pull in 4th gear from low speeds - and the overheating is 100% cured. However I think the improvement is mostly due to the old cat being in such a poor state that a lot of energy was being wasted in forcing the exhaust through it. Surprisingly, it did get through the 2019 MOT, a couple of months prior to the HG work, in this state. The idle became quite a bit rougher post-HG, it is not so easy to start, is more prone to stalling, and occasionally stumbles and stalls on throttle release. I have cleaned the IACV, which was full of soot, and this is now improved, if not completely eliminated. I have kind of ignored these idle issues as TATDS after major head work, as the results were so good otherwise. But maybe it's a clue as to what's gone wrong. About 6 weeks ago I had an occurence of misfiring. I checked the HT leads and found mild blemishes on the spring to no.1. That completely resolved the misfiring problem. I'm not aware of the injectors ever having been cleaned - so that sounds like a good thing to do.

Any advice on what to check/change? K-Series 1.8 VVC EU3, since last MOT new HG and head skimming, replacement cat. Car (and cat) were warm, straight from a 20 mile run. But the results were very similar on a previous attempt where it wasn't exercised much before the test. So perhaps less likely to be "cold cat syndrome". Fast idle test Engine Speed 2450-3050 rpm CO Max 0.3% Reading 2.00% FAIL HC Max 200 ppm Reading 155ppm PASS Lambda 0.95-1.09 Reading 0.94 FAIL Second fast idle test CO 2.38% HC 100ppm Lambda 0.93 Natural idle test CO Max 0.5% Reading 1.17% FAIL Further information: Lambda sensor has welded itself to the primary so cannot be immediately checked visually. But perhaps enough heat to weld it is enough to cook it?

... not forgetting the thick power lead which leads to the starter motor and then to the battery. So disconnect the battery first! Pretty much the same thing happened to me. I chose to simply replace the whole alternator with a reconditioned one. As it turned out I was glad I did as, aside from its (presumed) failed diode pack, the old alternator was just about ready for reconditioning itself! The replacement wasn't expensive and came in the post from Schmitz Rotary Engineering. It has worked perfectly ever since.